A continuous variable force transmission is known from U.S. Pat. No. 5,098,345. The continuously variable transmission disclosed in this publication includes a primary belt pulley which is accommodated on a primary shaft and a secondary belt pulley which is accommodated on a secondary shaft. A continuous belt-shaped transmission element is arranged between the primary and secondary belt pulleys and functions for transmitting torque between the two belt pulleys. In the transmission path of the torque, frictive slip preventing means are accommodated in such a manner that, in all operating conditions, it is ensured that the maximum torque, which is to be transmitted via the slip preventing means, in these conditions, is less than the slip torque of the continuous transmission element under these identical operating conditions. The transmission element is configured as a continuously running steel belt. The frictive slip preventing means contain clutch elements of the friction-plate type which are adjustable. The adjustability can take place especially via a fluid. For this purpose, a piston unit is provided which is mounted within a cylinder and which contains the fluid for bringing about the adjustability of the clutch.
According to this solution, only an inadequate consideration of the drive situation of the motor vehicle takes place during the determination of the applied contact of an automatic transmission stage (variator) or a coupling.